Slack and Microsoft Teams are two of the biggest enterprise communication tools out there, and the two services have developed a notable rivalry over the past few years. However, last week, Slack CEO announced that the company was working on an integration with Teams to allow users to make voice and video calls using Microsoft's service.

Now, the company has revealed that the integration is available in beta form, as reported by ZDNet. In addition to Teams, Slack can integrate with Zoom, Cisco Jabber, RingCentral, and Dialpad, and these integrations are specifically aimed at making calls to phone numbers from within Slack.

Despite the rivalry between the two companies' services, Slack offers a few integrations with other Microsoft products already, like OneDrive and Outlook. However, Teams is a direct competitor to Slack, and it's not like Slack doesn't have its own calling capabilities, so it's certainly interesting to see this integration happen. In the past, Slack's CEO has pointed out that the majority of Slack's customers also use Microsoft 365, which might help explain the decision.